15 Sep 2016

TREE ROOTS AND "BUILDERS"





OK, so i may have used the term "builder" harshly. There are a lot of people who damage tree roots on a daily basis without even realising it. You have the landscapers smashing surface roots with their lawnmowers. Construction workers and excavators cutting through a trees anchor system for their projects to be built or to lay new pipes and infrastructure. Even your average homeowner will seek to destroy roots growing near their houses or roots that maybe inflicting on a perfect lawn they have manicured for years. The point is, tree roots are very much put at the back of the priority list and are the first thing to be axed, when a choice has to be made.

Roots are arguably the most neglected topic when dealing with a tree. Probably because they are not visible to the naked eye they seem to get forgotten about. We get a lot of clients who phone up and ask us for a quote to remove a dead tree in their garden, but don't necessarily want to know why it has died. Trees don't just die over night. Its a long, drawn out suffering and symptoms are either ignored, or not cared about. But the symptoms are always there too see and we would like to share with you a few examples of root dysfunction leading to tree death.


A building site with a lack of respect for trees and their roots.

 Before we get into that lets talk on some basic anatomy of tree roots. There 3 main functions of a trees root system:


  1. Support a trees vast and heavy structure from falling to the ground.
  2. Absorb nutrients and water from the surrounding soil and trans locate them higher into the canopy to be used for food production.
  3. Store energy for when is tree is stressed or suffering and can't produce enough food for its survival.


Now, we expect a lot from trees. We want them to be strong and safe, healthy and vibrant living specimens, yet we don't bother to care for them properly. A basic needs of a tree is water and they absorb this through their roots and trans locate it to where its needed within the canopy. Now, when was the last time you watered your trees? We don't, right. We don't because they survive without us intervening however we believe there is a big difference between a tree surviving, and a tree thriving.
A thriving tree will have energy reserves to call on when conditions may not be favourable for growth.  It will use these reserves until conditions pick up and can start producing food again, it will also look to replace those reserves that were used necessarily. A surviving tree will do just that............. survive. It will produce its food to live on but will have nothing in the tank for when times get tough. When a surviving tree starts to lose this inevitable battle, symptoms will appear in many ways which may include:

  • A thin canopy.
  • Yellowing or browning of leaves.
  • Leaves becoming smaller or larger than 'normal'.
  • Isolated die back usually starting at the higher tips of the tree.
  • Cracked or falling off bark.

What do tree roots need to function properly?

Tree roots have a few basic needs that don't need to be too scientific and should be attainable for most average people. Air and fertility within the soil. I list them this way round because air is the single, most important ingredient to root growth. Minerals and nutrients are generally found in most soils and if undernourished, can be easily replaced, but lack of air within the soil can be the start of bigger problems. 



Dumped soil at the base of this Cherry (Prunus sp) causing air deprivation.



Loose soil has space between the pores and air is able to move freely and deeply within the soil to where it is needed at the roots. Compacted soil can be a trees worse enemy as the pore space shrinks and less air, if any will penetrate through to the roots. You will likely be able to tell compacted soil as not even grass will readily grow in the area. You may have seen this with woodland footpaths. A frequent foot print on the same spot of soil is enough to cause compaction and that is how foot traffic paths are created. They take longer to be covered over by vegetation and so are marked as footpaths for future walkers. Now i know this analogy may seem extreme when dealing with tree roots and in a way, it is, but my aim was to get you thinking about tree roots and what can affect them. From frequent foot traffic, to cars parking under trees, to construction vehicles manoeuvring under canopies and to raising soil levels drastically. All will have a negative affect on a trees root system and all will set it back in one way or another.


CASE STUDY
Beautiful Cedrus deodar given an almost certain death penalty by raising the soil level.


This Cedrus deodar has had this beautiful Chinese stone garden built around its base and it looks lovely but, its a terrible idea in terms of tree health. A 2-3ft high retaining wall was built to facilitate approximately 4-5 tons of soil on top of the root area.  This will cause a lack oxygen and moisture availability for the roots consumption and symptoms of stress and/or decline will inevitably follow.

 


The owners thought they did a good thing.

Now i don't want to seem all doom gloom here but its important to consider a trees health when making long term and costly decisions. The owners of this Cedar felt as though they had made a good and considerate choice when choosing to include a trunk gap in their garden design. "We thought it would be a good hole for water to get to the roots". They had considered the tree in their decision but ultimately failed to involve a professional to help them come to a better, less tree destructive decisionIf they would have called in an arborist on first hand, they may not be left with random hole in the ground that once used to surround a tree. Now more expense may have to be spared to block up an unsightly hole in the event of the trees death. So if you are planning any works, or are concerned about a trees root system after past events, call a qualified and reputable arborist. they can come and assess the tree in its current state and help you come up with a plan that will be less invasive and a healthier choice for your beloved tree. It probably isn't too late to help a tree in need.